Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.6.99.3 (diaphorase)
5,903 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Muscular glycolytic fuels, intermediates and end-products (glycogen, glucose, glucose-6-phosphate, pyruvate, lactate), Krebs cycle intermediates (citrate, alpha-ketoglutarate, succinate, malate), related free amino acids (glutamate, alanine), ammonia, energy store (creatine phosphate), energy mediators (ATP, ADP, AMP) and energy charge potential were evaluated. Furthermore the maximum rate (Vmax) of the following enzyme activities was evaluated in the crude extract and/or mitochondrial fraction: for the anaerobic glycolytic pathway: hexokinase, phosphofructokinase, pyruvate kinase, lactate dehydrogenase; for the tricarboxylic acid cycle: citrate synthase, malate dehydrogenase; for the electron transfer chain: total NADH cytochrome c reductase, cytochrome oxidase. The rat gastrocnemius muscles were analysed in normoxia and after normobaric intermittent hypoxia (12 hours continuously daily; for 5 days). Cytidine and/or uridine were administered daily at the dose of 120 mg/kg, i.p., 30 min before the beginning of the experimental hypoxia. The intermittent normobaric hypoxia induced a biochemical adaptation characterized by the decrease of the muscular contents of creatine phosphate, citrate, alpha-ketoglutarate and glutamate. This adaptation occurred in the absence of significant changes in the Vmax of the tested muscle enzymes. In gastrocnemius muscle from hypoxic rats, the two biological pyrimidines tested induced various discrete, but often related, modifications of the contents of some Krebs cycle intermediates (i.e., alpha-ketoglutarate, malate) and related free amino acids (i.e., glutamate, alanine). In any case, the treatment with cytidine and/or uridine did not modify the Vmax of marker enzymes related to energy transduction.
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PMID:Modification of the skeletal muscle energy metabolism induced by intermittent normobaric hypoxia and treatment with biological pyrimidines. 402 89

This paper describes experiments conducted with membranous and soluble fractions obtained from Escherichia coli that had been grown on succinate, malate, or enriched glucose media. Oxidase and dehydrogenase activities were studied with the following substrates: nicotinamide adenine dinucleotide, reduced form (NADH), nicotinamide adenine dinucleotide phosphate, reduced form (NADPH), succinate, malate, isocitrate, glutamate, pyruvate, and alpha-ketoglutarate. Respiration was virtually insensitive to poisons that are commonly used to inhibit mitochondrial systems, namely, rotenone, antimycin, and azide. Succinate dehydrogenase and NADH, NADPH, and succinate oxidases were primarily membrane-bound whereas malate, isocitrate, and NADH dehydrogenases were predominantly soluble. It was observed that E. coli malate dehydrogenase could be assayed with the dye 2,6-dichlorophenol indophenol, but that porcine malate dehydrogenase activity could not be assayed, even in the presence of E. coli extracts. The characteristics of E. coli NADH dehydrogenase were shown to be markedly different from those of a mammalian enzyme. The enzyme activities for oxidation of Krebs cycle intermediates (malate, succinate, isocitrate) did not appear to be under coordinate genetic control.
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PMID:Respiration and protein synthesis in Escherichia coli membrane-envelope fragments. I. Oxidative activities with soluble substrates. 430 12

1. With reference to the post-operative dysfunction of the liver observed after halothane anaesthesia, the effects of the anaesthetic on some metabolic functions were studied in the isolated perfused rat liver. Oxygen uptake, glycolysis, gluconeogenesis and urea synthesis were affected by halothane at a concentration (2.5% of the gas phase) within the range used in clinical anaesthesia. 2. At this concentration of halothane uptake of oxygen was inhibited in livers from both fed and starved rats. 3. In livers from fed rats there was a 16-fold increase in lactate production. This was accompanied by a fivefold decrease in the tissue content of 2-oxoglutarate and a more than twofold decrease in citrate. The calculated [free NAD(+)]/[free NADH] ratio in both cytoplasm and mitochondria was lower in the halothane-exposed livers than in controls. 4. In livers of starved rats the rate of gluconeogenesis from lactate was decreased by halothane to 30% of the control rate. 5. Halothane inhibited gluconeogenesis from alanine and propionate to the same extent as from lactate, whereas glucose formation from dihydroxyacetone, glycerol, fructose and sorbitol was relatively unaffected. 6. During gluconeogenesis from 10mm-lactate the tissue content of ATP was decreased by 50%, glutamate by 50% and 2-oxoglutarate was decreased eightfold in the halothane-exposed livers. 7. Halothane decreased urea synthesis in the presence of 10mm-NH(4)Cl and 2mm-ornithine to 15% of the control rate. 8. The inhibitions of gluconeogenesis and urea synthesis were completely abolished within 15min of withdrawal of the anaesthetic. 9. The stimulation of uptake of oxygen brought about by the addition of lactate or precursors of urea was abolished by halothane. 10. Effects on gluconeogenesis similar to those of halothane occurred in livers exposed to the anaesthetic methoxyflurane, although normal rates were not restored on withdrawal of the drug. Other anaesthetic agents tested (ketamine-HCl and trichloroethylene) decreased gluconeogenesis to 66% of the control rate. 11. The inhibitory effects of halothane are consistent with an interference at the stage of the NADH dehydrogenase of the electron-transport chain.
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PMID:The effects of halothane (2-bromo-2-chloro-1,1,1-trifluoroethane) on glycolysis and biosynthetic processes of the isolated perfused rat liver. 434 8

Spheroplast membranes (spheroplast envelopes) of strain 2091 of group B Neisseria meningitidis were prepared by a procedure that included lysozyme treatment of the cells and osmotic lysis of the resulting spheroplasts. Electron microscopy revealed that the membranes consisted of two unit layers, generally parallel to each other. The membrane preparation migrated as a single component in a 40 to 70% sucrose gradient and consisted of 62% protein, 28% lipid, 9% ribonucleic acid, small amounts of carbohydrate, hexosamine, and deoxyribonucleic acid. When 1 or 10 mug (dry weight) was injected intravenously into rabbits, a mild pyrogenic reaction was elicited. In immunodiffusion tests, immune rabbit serum prepared against spheroplast membranes produced three major precipitin lines, with the homologous antigen solubilized with sodium dodecyl sulfate, and a single line with untreated antigen. The immune serum also reacted with a cell wall antigen, and to a lesser extent with some of the cytoplasmic antigens. Succinate dehydrogenase and reduced nicotinamide adenine dinucleotide (NADH) oxidase activities were found to be associated with the spheroplast membranes. NADH dehydrogenase also was associated with the membranes but was gradually released and recovered in other fractions. Glutamate-oxaloacetate transaminase, glutamate, glucose-6-phosphate, and isocitrate dehydrogenase activities were not found in the membrane preparation. About one-third of these enzymatic activities were recovered in the supernatant fluid after the sedimentation of the spheroplasts and two-thirds were recovered in the cytoplasmic fraction. N-acetylneuraminic acid (NAN)-condensing enzyme and cytidine monophosphate-NAN synthesizing enzyme also were identified in this organism. These enzymes were not associated with the membranes and were recovered from extracts from whole cells, spheroplasts, or cells exposed to osmotic shock, as well as from spheroplast supernatant and shock fluids. It is concluded that the spheroplast membranes of the strain of meningococci used in these studies are typical of those recovered from gram-negative bacteria.
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PMID:Characterization of spheroplast membranes of Neisseria meningitidis group B. 463 Jul 22

The effect of p-toluyl m-nitro-piperazine on energy conservation processes in rat liver mitochondria is presented. The drug showed an inhibitory effect on the three segments of the respiratory chain and on the ATPase system. NADH oxidase and NADH dehydrogenase activity was inhibited 100%. The velocity and amplitude of swelling induced by glutamate, succinate, ascorbate + TMPD, and ATP was significantly changed by p-toluyl m-nitro-piperazine. It was suggested that the general action of the drug on mitochondrial metabolism would be concerning with modifications on mitochondrial membrane.
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PMID:Possible mechanism of action of piperazine derivatives on liver mitochondria. I--Effect of p-toluyl m-nitro-piperazine (p-TNP). 627 80

The effects of furosemide on the mitochondrial electron transport system and on oxidative phosphorylation were explored. Furosemide above the concentration of 2 X 10(-3) mol/l was found to inhibit state 3 (ADP-dependent) respiration of the rat liver, renal cortex, renal medulla mitochondria. State 4 (resting) respiration was not affected by furosemide. Furosemide above the concentration of 7.5 X 10(-6) mol/l (substrate: glutamate-malate), and above 5 X 10(-6) mol/l (substrate: succinate) inhibited the respiration of rat liver mitochondria released by 3,5-di-tert-butyl-4-hydroxybenzylidenemalononitrile (SF 6847). This fact exactly indicates that furosemide inhibits the electron transport system in mitochondria. Furosemide at the concentration of 4 X 10(-3) mol/l inhibited the activities of NADH cytochrome c reductase and succinate cytochrome c reductase in sonicated mitochondrial subparticles of beef heart by 78.2% and 79.2% of control, respectively.
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PMID:Effect of furosemide on mitochondrial electron transport system and oxidative phosphorylation. 631 93

Baboons fed ethanol (50% of total calories) chronically develop ultrastructural alterations of hepatic mitochondria. To determine whether mitochondrial functions are also altered, mitochondria were isolated from nine baboons fed ethanol chronically and their pair-fed controls. At the fatty liver stage, ADP-stimulated respiration was depressed in ethanol-fed baboons by 59.4% with glutamate, 43.2% with acetaldehyde, 45.1% with succinate and 51.1% with ascorbate as substrates. A similar decrease was noted in the ADP/O ratio (14 to 28%) and respiratory control ratio (20 to 44%) with all substrates. Similar alterations of mitochondrial functions were observed in baboons with more advanced stages of liver disease, namely fibrosis. These changes after ethanol treatment were associated with decreases in the enzyme activities of mitochondrial respiratory chain: glutamate, NADH and succinate dehydrogenase (42, 24 and 28%, respectively), glutamate-, NADH- or succinate-cytochrome c reductase (42, 27 and 32%, respectively) and cytochrome oxidase (59.6%). The content of all cytochromes was also decreased in ethanol-fed baboons, especially aa3 (57%). Moreover, [14C]leucine incorporation into mitochondrial membranes was depressed by 21% after ethanol treatment. On the other hand, glutamate dehydrogenase activities of serum and cytosol in ethanol-fed baboons were significantly higher than those in pair-fed controls. Morphologically, mitochondria of ethanol-fed baboons were larger than those of pair-fed controls. However, the mitochondrial protein content per mitochondrial DNA was unchanged. From these results, we conclude that, morphologically and functionally, hepatic mitochondria in baboons are altered by chronic ethanol consumption; it is noteworthy that these changes are fully developed already at the fatty liver stage, and that morphological alteration appears to reflect the damage of mitochondrial membranes rather than an adaptive hypertrophy.
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PMID:Biochemical and morphological alterations of baboon hepatic mitochondria after chronic ethanol consumption. 653 46

In an in vitro study with rat liver, ammonium meta vanadate (NH4VO3) was found to inhibit microsomal ketamine N-demethylation, lipid peroxidation, and hydrogen peroxide formation; to have no effects on 4-methylaminoantipyrine N-demethylation and on glucuronyltransferase I activity, and to enhance glucuronyltransferase II. Mitochondrial succinate dehydrogenase and cytochrome c reductase were inhibited but cytochrome oxidase activity was enhanced by ammonium vanadate. Ammonium meta vanadate increased malate dehydrogenase activity but had no effect on glutamate, lactate, glycerophosphate, isocitrate, glucose-6-phosphate, and 6-phosphogluconate dehydrogenases.
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PMID:Action of ammonium meta vanadate on hepatic enzymes in vitro. 660 35

A new peroxide compound (ML-X) was isolated from an autoxidation product of methyl linoleate and was determined as methyl 9-hydroperoxy-12, 13-epoxy-10-octadecenoate. This compound inhibited state 3 respiration of rat heart- and liver mitochondria when glutamate and malate were used as substrates, but not when the substrate was succinate. State 4 respiration of mitochondria was not affected when glutamate-malate was used as the substrate, but it was stimulated when the substrate was succinate. ML-X inhibited oxidative phosphorylation of the mitochondria and abolished the membrane potential formed by respiration or by added ATP. NADH oxidase activity of submitochondrial particles was inhibited by ML-X but succinate oxidase activity was not inhibited. NADH-acceptor reductase activities of submitochondrial particles were inhibited by ML-X to the same extents as by rotenone. These findings show that ML-X has dual effects on mitochondrial respiration as (1) an inhibitor of NADH dehydrogenase complex and (2) an uncoupler. Neither methyl linoleate monohydroperoxide nor methyl epoxy stearate has such effects. ML-X is a new type of inhibitor-uncoupler of mitochondrial respiration in which hydroperoxy- and epoxy groups co-operate.
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PMID:Methyl hydroperoxy-epoxy-octadecenoate as an autoxidation product of methyl linoleate: a new inhibitor-uncoupler of mitochondrial respiration. 717 40

The recent discovery of the identify of nitric oxide synthase with the reduced nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) has powerfully stimulated the anatomical localization of sites of nitric oxide synthesis in the nervous system. In the present study the widely used light microscopical technique for NADPH-d staining was adapted to the electron microscopical level by applying the tetrazolium salt 2-(2'-benzothiazolyl)-5-styryl-3-(4'-phthalhydrazidyl)tetrazolium chloride (BSPT) which produces an electron-dense reaction product, BSPT-formazan. Predominantly membranes of the endoplasmic reticulum were stained. Apart from singular heavily labeled neurons, a majority of nerve cells, light microscopically "unstained", shows sporadically formazan deposits, and, likewise, but regionally different, a few astroglial cells. Lesions induced by the glutamate agonists quinolinic acid and alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) display surviving neurons, which are predominantly stained for NADPH-d. Astroglial cells within lesioned areas exhibit increased amounts of reaction product, apparently as a consequence of enzyme induction.
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PMID:Nitric oxide synthase in the brain: light and electron microscopical findings based on the NADPH-diaphorase reaction. 753 22


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